Vladimir Potapov
On the first screenshot marked "window" Capitol (zemetka number 1), remember this screen. The second screenshot marked illuminated window (note 2,3 and 4), as well as the center of the light source (note 5). While the focus on this. If you imagine everything as it is in fact what notes 2,3 and 4 should be the most illuminated and darkened windows opposite directions. Likely mask is wrong layer. Note number 6 and number 7 puts everything in its place, if still not clear, then you can follow this link to read about the speed of light
ru.wikipedia.org/wiki/Скорость_света . Simply put by roller just created layer so that's painted beam and create a keyframe to change transparency, to put it mildly is not applicable to light. Understand my post useless Most of the band members, but almost 21% who voted for it "start UFO", it should read, and then read again.